W77L32 Datasheet, PDF (5/76 Pages) Winbond – 8-BIT MICROCONTROLLER

W77L32/W77L032A/W77M032A
4. PIN DESCRIPTION
SYMBOL
EA
TYPE
DESCRIPTIONS
I EXTERNAL ACCESS ENABLE: It should be kept low.
PSEN
O ^{PROGRAM STORE ENABLE: PSEN enables the external ROM data onto the Port 0}
address/data bus during fetch and MOVC operations.
ALE
O
ADDRESS LATCH ENABLE: ALE is used to enable the address latch that separates
the address from the data on Port 0.
RST
I
RESET: A high on this pin for two machine cycles while the oscillator is running resets
the device.
XTAL1
XTAL2
I
CRYSTAL1: This is the crystal oscillator input. This pin may be driven by an external
clock.
O CRYSTAL2: This is the crystal oscillator output. It is the inversion of XTAL1.
VSS
I GROUND: Ground potential
VDD
I POWER SUPPLY: Supply voltage for operation.
P0.0 − P0.7
I/O
PORT 0: Port 0 is an open-drain bi-directional I/O port. This port also provides a
multiplexed low order address/data bus during accesses to external memory.
PORT 1: Port 1 is a bi-directional I/O port with internal pull-ups. The bits have alternate
functions which are described below:
T2(P1.0): Timer/Counter 2 external count input
T2EX(P1.1): Timer/Counter 2 Reload/Capture/Direction control
RXD1(P1.2): Serial port 1 RXD
P1.0 − P1.7 I/O TXD1(P1.3): Serial port 1 TXD
INT2(P1.4) : External Interrupt 2
INT3 (P1.5): External Interrupt 3
INT4(P1.6) : External Interrupt 4
INT5 (P1.7): External Interrupt 5
P2.0 − P2.7
I/O
PORT 2: Port 2 is a bi-directional I/O port with internal pull-ups. This port also provides
the upper address bits for accesses to external memory.
PORT 3: Port 3 is a bi-directional I/O port with internal pull-ups. All bits have alternate
functions, which are described below:
RXD(P3.0) : Serial Port 0 input
TXD(P3.1) : Serial Port 0 output
INT0 (P3.2): External Interrupt 0
P3.0 − P3.7 I/O _{INT1 (P3.3): External Interrupt 1}
T0(P3.4) : Timer 0 External Input
T1(P3.5) : Timer 1 External Input
WR (P3.6) : External Data Memory Write Strobe
RD (P3.7) : External Data Memory Read Strobe
PORT 4: Port 4 is a 4-bit bi-directional I/O port. The P4.0 also provides the alternate
P4.0 − P4.3 I/O
function WAIT which is the wait state control signal.
* Note: TYPE I: input, O: output, I/O: bi-directional.
Publication Release Date: April 17, 2007
-5-
Revision A6